If you're looking for alternative words to express the vastness or greatness of something, consider these synonyms for the word "tremendously." Instead of using "tremendously," try using "enormously," "immensely," or "exceedingly." "Extremely" and "intensely" are also excellent choices to emphasize the strength of a particular situation or experience. "Mightily" can be used in casual conversation, while "colossally" and "monstrously" are more impactful words that could be used in a more dramatic context. Whatever synonym you choose, make sure it fits the tone and context of your writing or speech.